Systems and methods for wire deposited additive manufacturing using titanium

ABSTRACT

A metallic part is disclosed. The part may comprise a functionally graded monolithic structure characterized by a variation between a first material composition of a first structural element and a second material composition of at least one of a second structural element. The first material composition may comprise an alpha-beta titanium alloy. The second material composition may comprise a beta titanium alloy.

FIELD

The disclosure generally relates to the manufacture of aerospacecomponents using wires suitable for additive manufacturing and moreparticularly to the wires being produced by forming a sintered billet oftitanium and other metallic powders.

BACKGROUND

Aircraft landing gear designs incorporate large structural componentsmade from high strength titanium alloys. Powder based additivemanufacturing techniques, such as powder bed, for titanium alloy landinggear components are unsuited for producing large parts. Wire depositionadditive manufacturing techniques may be used to form large parts.However, existing wire feedstocks for titanium alloys tend to be highcost and tend to have reduced tensile and/or fatigue strength incomparison to wrought processed material.

SUMMARY

In various embodiments, a metallic part comprises a functionally gradedmonolithic structure characterized by a variation between a firstmaterial composition of a first structural element and a second materialcomposition of a second structural element, wherein each of the firstmaterial composition and the second material composition comprises atleast one of a titanium metal or an alloy.

In various embodiments, the first material composition comprises analpha-beta titanium alloy. In various embodiments, the second materialcomposition comprises a beta titanium alloy. In various embodiments, thesecond structural element is composed of a heat treated wire drawn froma sintered billet of powdered metals deposited integrally with the firststructural element. In various embodiments, the sintered billet ofpowdered metals comprises between 4% and 6% by weight iron, between 0.5%to 2% by weight aluminum, and between 6% to 9% by weight vanadium. Invarious embodiments, the heat treated wire comprises between 0.25% and0.50% by weight oxygen and between 0.001% and 0.015% by weight hydrogen.In various embodiments, the first structural element comprises a baseplate having between 5.5% and 6.75% by weight aluminum and between 3.5%to 4.5% by weight vanadium. In various embodiments, the secondstructural element comprises a flange portion. In various embodiments,the first structural element and the second structural element definesone of a “C” shaped channel, a “T” shaped beam, an “S” shaped beam, an“I” shaped beam, an “H” shaped beam, or an “L” shaped beam.

In various embodiments, an article of manufacture including a metalliccomponent comprising a functionally graded monolithic structurecharacterized by a variation between a first material composition of afirst structural element and a second material composition of a secondstructural element, wherein each of the first material composition andthe second material composition comprises at least one of a titaniummetal or an alloy, wherein the second structural element is formed of awire feedstock, wherein the wire feedstock comprising a heat treatedwire drawn from a sintered billet of powdered metals, the powderedmetals comprising titanium hydride, iron, vanadium, and aluminum.

In various embodiments, the first material composition comprises analpha beta titanium alloy. In various embodiments, the second materialcomposition comprises a beta titanium alloy. The sintered billet ofpowdered metals may comprise between 4% and 6% by weight iron, between0.5% to 2% by weight aluminum, and between 6% to 9% by weight vanadium.The heat treated wire may comprise between 0.25% and 0.50% by weightoxygen and between 0.001% and 0.015% by weight hydrogen. In variousembodiments, the heat treated wire is heat treated by at least one ofannealing, solutionizing, or aging. In various embodiments, the heattreated wire may undergo at least one of a beta phase transformation, abeta anneal, or an alpha-beta anneal during the at least one ofannealing, solutionizing, or aging.

In various embodiments, a method of additive manufacturing comprisesmixing a plurality of powdered metals comprising titanium, iron,vanadium, and aluminum to produce a powder blend, cold isostaticpressing and sintering the powder blend to form a billet, performing awire forming operation on the billet to produce a worked wire, heattreating the worked wire to produce a heat treated wire, loading a firststructural element into an additive manufacturing machine, printing asecond structural element of the heat treated wire integral to the firststructural element to form a part, and heat treating the part togenerate a functionally graded monolithic structure. In variousembodiments, the titanium is a titanium hydride powder and the firststructural element comprises a substantially Iron free Titanium alloy.In various embodiments, the powder blend comprises between 4% and 6% byweight iron, between 0.5% to 2% by weight aluminum, and between 6% to 9%by weight vanadium. In various embodiments, the sintering is performedbetween 900° F. and 1600° F. and under a vacuum.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated hereinotherwise. These features and elements as well as the operation of thedisclosed embodiments will become more apparent in light of thefollowing description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosures, however, maybest be obtained by referring to the detailed description and claimswhen considered in connection with the drawing figures, wherein likenumerals denote like elements.

FIG. 1A illustrates an additively manufactured part, in accordance withvarious embodiments;

FIG. 1B illustrates an additively manufactured part, in accordance withvarious embodiments;

FIG. 2A illustrates a method for titanium wire additive manufacturing,in accordance with various embodiments; and

FIG. 2B illustrates a continuation of a method from FIG. 2A for titaniumwire additive manufacturing, in accordance with various embodiments; and

FIG. 3 illustrates a method of additive manufacturing, in accordancewith various embodiments.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration and their best mode. While these exemplary embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the disclosures, it should be understood that other embodimentsmay be realized and that logical, chemical, and mechanical changes maybe made without departing from the spirit and scope of the disclosures.Thus, the detailed description herein is presented for purposes ofillustration only and not of limitation. For example, the steps recitedin any of the method or process descriptions may be executed in anyorder and are not necessarily limited to the order presented.Furthermore, any reference to singular includes plural embodiments, andany reference to more than one component or step may include a singularembodiment or step. Also, any reference to attached, fixed, connected orthe like may include permanent, removable, temporary, partial, fulland/or any other possible attachment option. Additionally, any referenceto without contact (or similar phrases) may also include reduced contactor minimal contact.

Titanium alloy Ti-185 has a relatively high tensile strength; however,the high iron percentage of the alloy causes segregation duringconventional melting. Stated another way, titanium alloys having ironcompositions above 3% by weight tend to have an iron composition proneto segregation by conventional manufacture via melting. Powdermetallurgy techniques such as, for example, pressing and sintering mayovercome the segregation issues induced in conventional melt metallurgy,thereby enabling a lower cost part. Alloying powder may be eitherelemental powders (e.g., Ti, Fe, V, Al), master alloy powders, or acombination thereof. Sintered billets may be drawn or otherwise workedinto a wire feedstock for additive manufacturing operations. In thisregard, large, high strength titanium alloy components such as, forexample, pistons, bogie beams, torque links, brake rods, and/or the likemay be produced at reduced cost. Additionally, additive manufacturingaccording to the process described herein may tend to overcome macrosegregation issues encountered in conventional melt metallurgy andbenefit of enhanced fatigue and ultimate strength.

With reference to FIGS. 1A and 1B, an additively manufactured part 100is illustrated with XYZ-axes provided for reference in perspective viewas shown in FIG. 1A and in cross section through the XY-plane as shownin FIG. 1B in accordance with various embodiments. Part 100 maycomprises a functionally graded structure characterized by a variationin structural material composition between structural elements of amonolithic structure. In this regard, the monolithic structure may betailored to the particular engineering design loads for each structuralelement as a function of the material composition of the structuralelement (i.e. functionally graded). Part 100 may comprise a firststructural element such as a base plate 102. In various embodiments thefirst structural element may comprise one of a plate, a tube, a rod, ora hollow structure. Base plate 102 comprises a first metallic materialsuch as one of a metal, an alloy, a titanium alloy, and/or the like. Invarious embodiments, the first structural element such as base plate 102comprises an iron free titanium alloy, or substantially less iron freetitanium alloy of up to 2.5 wt. % iron, or an alpha-beta titanium alloysuch as, for example, Ti-64 alloy (Ti-6Al-4V) conforming to SAE AMS 4911comprising aluminum at 5.5-6.75 wt. %, vanadium at 3.5-4.5 wt. %,yttrium at not more than 0.005 wt. %, iron at not more than 0.3 wt. %,carbon at not more than 0.08 wt. %, nitrogen at not more than 0.05 wt.%, hydrogen at not more than 0.015 wt. %, a total of other elements atnot more than 0.4 wt. %, and with the balance of titanium. Base plate102 may be a rectilinear plate comprising a first side 104, a secondside 106, a third side 108, and a fourth side 110 defining a first face112 and a second face 114. In various embodiments, base plate 102 may beof any alpha-beta alloy known to those skilled in the art where lowmaterial cost tends to be preferred over material strength.

In various embodiments, one or more second structural elements such asfirst 116, second 118, third 120, and fourth 122 flange portions may beformed from the base plate 102. Each of the second structural elementsmay comprise a second metallic material such as one of a metal, analloy, a titanium alloy, and/or the like. In various embodiments, theflange portions (116, 118, 120, 122) comprise a titanium-iron alloy or abeta titanium alloy such as, for example, Ti-185 alloy (Ti-1Al-8V-5Fe)comprising aluminum at 0.8-1.5 wt. %, vanadium at 7.5-8.5 wt. %, iron at4-6 wt. %, oxygen at 0.25-0.5 wt. %, nitrogen at not more than 0.070 wt.%, carbon at not more than 0.050 wt. %, and with the balance oftitanium. Each of the second structural elements, such as the flangeportions (116, 118, 120, 122), may be formed integrally with the firststructural element, such as the base plate 102, via an additivemanufacturing process. In various embodiments, the second structuralelements may extend radially outward of the first structural elementsuch as, for example, the tube and/or hollow shape. The additivemanufacturing process may include one of selective laser melting,selective metal sintering, direct energy deposition, wire deposition,wire arc, and/or any suitable additive manufacturing process known tothose in the art.

In various embodiments, one or more second structural elements may beconfigured to alter the shape of additively manufactured part 100 suchas, for example, an “I” or “H” shaped beam as illustrated in FIGS. 1Aand 1B. For example, part 100 may comprise base plate 102 having firstflange portion 116 proximate first side 104 with second flange portion118 proximate second side 106. Each of the first flange portion 116 andthe second flange portion 118 may extend perpendicular to base plate 102from first face 112. In this regard, additively manufactured part 100may form a relatively “C” shaped channel. In another embodiment,additively manufactured part 100 may comprise base plate 102 having thefirst flange portion 116 and the third flange portion 120 proximatefirst side 104. The first flange portion may extend perpendicular tobase plate 102 from first face 112 and the third flange portion 120 mayextend perpendicular to base plate 102 from second face 114. In thisregard, additively manufactured part 100 may form a relatively “T”shaped beam.

In various embodiments, additively manufactured part 100 may comprisebase plate 102 having the first flange portion 116 proximate first side104 and the fourth flange portion 122 proximate second side 106. Thefirst flange portion may extend perpendicular to base plate 102 fromfirst face 112 and the fourth flange portion 122 may extendperpendicular to base plate 102 from second face 114. In this regard,additively manufactured part 100 may form a relatively “S” shaped beam.In another embodiment, additively manufactured part 100 may comprisebase plate 102 having the first flange portion 116 proximate first side104. The first flange portion may extend perpendicular to base plate 102from first face 112. In this regard, additively manufactured part 100may form a relatively “L” shaped beam.

With additional reference to FIG. 2A, a method for titanium wireadditive manufacturing is illustrated according to various embodiments.A plurality of powdered metals 202 comprising titanium and iron areadded to powder blender 204 and blended to consistency to powder blend206. In various embodiments, powder blend 206 may comprise titanium andiron and any of oxygen, aluminum, vanadium, and/or hydrogen. Powderedmetals 202 may include titanium hydride powder. Powder blend 206 may bebetween 4% and 6% by weight iron, between 0.5% to 2% by weight aluminum,and between 6% to 9% by weight vanadium. The input powders may containoxygen levels between 0.25% and 0.5% by weight and hydrogen levels up to0.015% by weight or between 0.001% and 0.015% by weight. In variousembodiments, powdered metals consist of Al—V master alloy and Feelemental powder blended with TiH₂ powder. The billet elemental weightpercent may be adjusted to account for vaporization of elements such asaluminum during the wire-fed additive process tending thereby to ensurethe additive manufactured part is within a desired weight percent limit.In various embodiments, the billet shape may be a solid round or othershape as appropriate to input stock for wire drawing.

Powder blend 206 is loaded into sintering furnace 208 which appliesforce 210 to compact the powder blend 206 and heat to sinter the powderblend 206, thereby forming billet 212. In various embodiments, thepowder blend 206 may be compressed by cold isostatic pressing to form acompressed shape prior to sintering. In various embodiments, sinteringfurnace 208 may be a vacuum sintering furnace and powder blend 206 maybe compressed and heated under a vacuum. In various embodiments, thecompressed powder blend 206 may be heated to between 900° F. [483° C.]and 1600° F. [871° C.] for the sintering operation. In this regard, thesintered billet may undergo beta phase transformation. Sintering thepowder blend 206 may include removing gasses evolved from the powderblend 206 during sintering and sintering furnace 208 may include a gasremoval system and/or control system. In various embodiments, oxygen,nitrogen, and/or hydrogen may be removed from the powder blend 206during sintering. In various embodiments, billet 212 may undergo anannealing cycle subsequent to sintering and prior to wire formingoperations 216. In various embodiments, the annealing cycle temperaturesmay be between 1200° F. [649° C.]and 1400° F. [760° C.].

Billet 212 may receive an initial anti-oxidation coating 214 prior toundergoing wire forming operations 216. In various embodiments, wireforming operations 216 may draw the billet 212 that has been sinteredinto a wire of a desired diameter. Wire forming operations 216 mayinclude rotary swaging 218 via an array of swaging dies 220 which exertforce circumferentially about billet 212, thereby reducing its diameter.Wire forming operations 216 may also include rolling 222 of billet 212through rollers 224, thereby reducing its diameter. Additionally, wireforming operations 216 may include extruding 226 of billet 212 throughdie 228, thereby reducing its diameter. A plurality of wire formingoperations 216 may be conducted repeatedly or sequentially as requiredto achieve a desired wire diameter for a worked wire 230. In variousembodiments, the diameter of billet 212 may be reduced by wire formingoperations 216 to a wire diameter between 0.0104 in [0.265 mm] and 0.156in [4.0 mm]. In various embodiments, anti-oxidation coating 214 may bereapplied between successive wire forming operations 216 as rotaryswaging 218, rolling 222, and extruding 226 tend to remove the coating.In various embodiments, the worked billet 212 may undergo a metalpickling treatment between wire forming operations 216. In this regard,scale formation on billet 212, impurity, and oxygen uptake of billet 212are reduced. In various embodiments, any of wire forming operations 216may be conducted in a vacuum or under an inert gas such as, for example,argon.

In various embodiments, worked wire 230 may undergo one or more heattreatment operations 232, for example, in a heat treat oven 234 betweenwire forming operations 216 (e.g., intermediate heat treatments) and/orwhen worked wire 230 has achieved the desired final diameter (e.g.,final heat treatment) In this regard, crack formation and oxideformation during wire forming operations 216 may be reduced. Heattreatment operations may include solutionizing heat treatment, aging,and/or annealing. In various embodiments, heat treatments may include abeta anneal and an alpha beta anneal. For example, annealing between1550° F. [843° C.] and 1600° F. [871° C.] or annealing between 1200° F.[649° C.] and 1400° F. [760° C.] or annealing between 1300° F. [705° C.]and 1350° F. [732° C.]. In various embodiments, a solutionizing heattreatment may be between 1350° F. [732° C.] and 1450° F. [788° C.]. Invarious embodiments, an aging heat treatment may be between 800° F.[427° C.] and 1100° F. [593° C.] or may be adjusted to achieve a desiredmaterial property for wire manufacture. In various embodiments, the heattreated wire may have between 0.001% and 0.015% by weight hydrogen andmay have between 0.25% and 0.5% by weight oxygen.

Heat treated alloy wire 236 may be coiled 238 onto feed spools 240 andloaded in a wirefeed additive manufacturing machine 242 configured forheat treated alloy wire 236. Wirefeed additive manufacturing machine 242may comprise hardware and/or software configured to perform additivemanufacturing of an aerospace component. In various embodiments,wirefeed additive manufacturing may include laser wire metal deposition,electron beam additive manufacturing, wire arc additive manufacturingand/or the like. In various embodiments, wirefeed additive manufacturingmachine 242 may be configured to deposit the heat treated wire on asubstrate. For example, the wirefeed additive manufacturing machine 242may be configured with a turntable, gantry style or rotating head andtailstock style. In various embodiments, the wirefeed additivemanufacturing machine 242 may incorporate a single or a multiplewirefeed system and be capable of delivering the heat treated alloy wire236 at a rate of of 0.5 in/min [1.27 cm/min] to 25 in/min [63.5 cm/min]and may have deposition rates between 1 and 20 lbs/hour [0.45 and 9kg/hr]. Wirefeed additive manufacturing machine 242 may produce ametallic aerospace component 244 from heat treated alloy wire 236.Metallic aerospace component 244 may undergo a component heat treatprocess 245 similar to heat treatment operations 232.

In various embodiments and with additional reference to FIG. 3, a method300 of manufacturing a functionally graded metallic part is illustrated.Method 300 may include loading a first structural element into anadditive manufacturing machine (step 302). For example, base plate 102may be loaded in to wirefeed additive manufacturing machine 242. Method300 includes printing a second structural element integral to the firststructural element to form a part (step 304). For example, heat treatedalloy wire 236 may be continuously deposited over first face 112 ofplate 102 to form a flange portion such as, for example, first flangeportion 116, of part 100. Method 300 may include heat treating the part(step 306) for example by one of annealing, solutionizing, or aging togenerate a functionally graded monolithic structure. As will beappreciated by those skilled in the art, the functionally gradedmonolithic structure may benefit of as printed part heat treating andheat treating variables may be tailored in consideration of the firstmaterial composition and the second material composition. The heattreating temperature may tend to drive similar microstructuraltransformations, such as, for example overlapping the annealingtemperatures. In one embodiment, for example incorporating a Ti-6Al-4Vbase plate and additive manufactured Ti-185 features having annealingtemperatures of 1300° F. [705° C.] to 1650° F. [899° C.] and 1250° F.[677° C.] to 1350° F. [732° C.], respectively, the as printed structuremay be annealed between 1300° F. [705° C.] and 1350° F. [732° C.].Alternatively, the heat treating temperature may drive differentmicrostructural transformations. In another embodiment, an alpha-betaannealing temperature of Ti-6Al-4V may serve as a beta annealingtemperature for Ti-185, as the beta transus temperature for Ti-185(1525° F. [830° C.]) is markedly different than for Ti-6Al-4V (1825° F.[996° C.]). Such a heat treatment may result in a functionally gradedpart having differing microstructures tailored for a desired structuralperformance of a part feature such as, for example, a Widmenstattan orlamella structure for one titanium alloy (e.g., the first materialcomposition), and a mill annealed microstructure for the other (e.g.,the second material composition). Method 300 may include finishmachining the part (step 306) such as, for example, by a subtractivemanufacturing process.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the disclosures.

The scope of the disclosures is accordingly to be limited by nothingother than the appended claims, in which reference to an element in thesingular is not intended to mean “one and only one” unless explicitly sostated, but rather “one or more.” Moreover, where a phrase similar to“at least one of A, B, or C” is used in the claims, it is intended thatthe phrase be interpreted to mean that A alone may be present in anembodiment, B alone may be present in an embodiment, C alone may bepresent in an embodiment, or that any combination of the elements A, Band C may be present in a single embodiment; for example, A and B, A andC, B and C, or A and B and C. Different cross-hatching is usedthroughout the figures to denote different parts but not necessarily todenote the same or different materials.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”, “anexample embodiment”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiment

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises”, “comprising”, or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

What is claimed is:
 1. A metallic part, comprising: a functionallygraded monolithic structure characterized by a variation between a firstmaterial composition of a first structural element and a second materialcomposition of a second structural element, wherein the first materialcomposition comprises an alpha-beta titanium alloy and the secondmaterial composition comprises a beta titanium alloy, wherein the secondstructural element is monolithic with a surface of the first structuralelement. 2-4. (canceled)
 5. The metallic part of claim 1, wherein thesecond structural element comprises 5% to 6% by weight iron, 0.5% to 2%by weight aluminum, and 6% to 9% by weight vanadium.
 6. The metallicpart of claim 5, wherein the heat treated wire comprises 0.25% to 0.50%by weight oxygen and 0.001% to 0.015% by weight hydrogen.
 7. Themetallic part of claim 1, wherein the first structural element comprisesa base plate having 5.5% to 6.75% by weight aluminum and 3.5% to 4.5% byweight vanadium.
 8. The metallic part of claim 7, wherein the secondstructural element comprises a flange portion.
 9. The metallic part ofclaim 8, wherein the first structural element and the second structuralelement defines one of a “C” shaped channel, a “T” shaped beam, an “S”shaped beam, an “I” shaped beam, an “H” shaped beam, or an “L” shapedbeam.
 10. An article of manufacture including a metallic componentcomprising: a functionally graded monolithic structure characterized bya variation between a first material composition of a first structuralelement and a second material composition of a second structuralelement, wherein each of the first material composition and the secondmaterial composition comprises at least one of a titanium metal or analloy, wherein the second structural element is formed of a wirefeedstock, wherein the wire feedstock comprises a heat treated wiredrawn from a sintered billet of powdered metals, and the sintered billetof powdered metals comprise titanium hydride, iron, vanadium, andaluminum.
 11. The article of manufacture of claim 10 wherein, whereinthe first material composition comprises a substantially iron freetitanium alloy.
 12. The article of manufacture claim 11, wherein thesecond material composition comprises a titanium alloy with an ironcomposition 3% by weight or more.
 13. The article of manufacture ofclaim 12, wherein the sintered billet of powdered metals comprisebetween 4% and 6% by weight iron, between 0.5% to 2% by weight aluminum,and between 6% to 9% by weight vanadium.
 14. The article of manufactureof claim 12, wherein the heat treated wire comprises between 0.25% and0.50% by weight oxygen and between 0.001% and 0.015% by weight hydrogen.15. The article of manufacture of claim 14, wherein the heat treatedwire is heat treated by at least one of annealing, solutionizing, oraging.
 16. The article of manufacture of claim 15, wherein the heattreated wire has undergone at least one of a beta phase transformation,a beta anneal, or an alpha beta anneal during the at least one ofannealing, solutionizing, or aging.
 17. A method of additivemanufacturing, comprising: mixing a plurality of powdered metalscomprising titanium, iron, vanadium, and aluminum to produce a powderblend; cold isostatic pressing and sintering the powder blend to form abillet; performing a wire forming operation on the billet to produce aworked wire; heat treating the worked wire to produce a heat treatedwire; loading a first structural element into an additive manufacturingmachine; printing a second structural element of the heat treated wireintegral to the first structural element to form a part, and heattreating the part to generate a functionally graded monolithicstructure.
 18. The method of claim 17, wherein the titanium is atitanium hydride powder and the first structural element comprises asubstantially Iron free Titanium alloy.
 19. The method of claim 18,wherein the powder blend comprises between 4% and 6% by weight iron,between 0.5% to 2% by weight aluminum, and between 6% to 9% by weightvanadium.
 20. The method of claim 19, wherein the sintering is performedbetween 900° F. and 1600° F. and under a vacuum.